He himself, in one of his unveracious accounts of his career, states that he was educated at Enniskillen school, County Fermanagh, and afterwards at Trinity College, Dublin, but his name does not appear on the list of graduates.
In 1675 he married Anne Yeabsly, and five years later, though she was still living, he went through the form of marriage with Mary, daughter of Simon Hutt, a Cavan innkeeper, who was thenceforth the favoured companion in his wanderings and accomplice in his crimes.
Soon after 1680 Young managed to procure admission to deacon's orders at the hands of John Roan, Bishop of Killaloe, whom he circumvented by forging certificates of his learning and moral character.
From Bury gaol, on 30 September 1684, Young had written a long letter to Archbishop Sancroft, with an entirely novel account of his parentage and early life, expressing his mortal hatred of "discentors, especially that damnable faction of Presbytery", and stating that he had been put upon "the hellish and durty stratageme" of forging testimonials by one Wright, a non-existent "scrivener of Oxford".
At length in 1687 the imposture came under the notice of the archbishop, who caused to be inserted in the London Gazette (September and October 1687) advertisements warning the charitable to beware of Mrs. Jones and Robert Smith (i.e. Young and his paramour).
Young next gave himself out as a grave Irish clergyman of good preferment, but a victim of Tyrconnel's persecuting fury; some funds were necessary to support this character, and these he seems to have obtained by a series of highly successful frauds at St. Albans, where he had secured the corrupt connivance of the postmaster.
Forming a design of a wealthy marriage, Young was now anxious to get rid of Mary Hutt; but at this juncture the pair were betrayed to one of their victims, and lodged in Newgate on a charge of forgery.
While lying in Newgate he determined upon reverting to this branch of his profession and fabricating a sham plot, and with this object in view he addressed himself in the first instance to Tillotson.
Blackhead, affecting great reverence for the entourage of a bishop, asked the butler to show him Sprat's study, with a view of concealing the traitorous document among the papers on the episcopal table.
They thought Young's story plausible enough to order Sprat's arrest, and messengers were sent down to Bromley on 7 May 1692 with a warrant from Nottingham to take the bishop into custody, and to search his apartments for the signed instrument in which the alleged conspirators avowed their aims.
Finding the bishop's story corroborated by his servants at all points, and greatly relieved by the victory of La Hogue, the privy councillors turned sharply on Blackhead, who lost his nerve and finally blurted out the truth.
On his return to Newgate Young attempted to suborn a half-starved wretch named Holland to take Blackhead's place, and to support him with newly devised evidence against Marlborough and Sprat.
Having effected his escape from the King's Bench Prison on 12 December 1698, Young seems to have turned to coining for a livelihood, and early in April 1700 he was arrested for this offence and tried at the Old Bailey.
In a "Paper delivered by Robert Young" to John Allen, the ordinary of Newgate, and published on 20 April 1700, the criminal frankly confesses "I have injured my Neighbour so often by Forgeries, Cheats, &c., that I think it is scarce possible to recount them".